Support for the roof of an excavation

ABSTRACT

A base has one side facing towards and another side facing away from the face of an excavation. A shield has an end portion that is pivoted to the base in the region of the other side thereof, and it has another end portion that is closer to the one side. An adjustable support engages the base and the shield for supporting the latter in upright position. An end cap is pivotably mounted on the other end portion of the shield. Interdigitating portions are provided on the end cap and on the other end portion of the shield and remain in interdigitating engagement with one another in pivoted positions of the end cap relative to the other end portion of the shield, so as to avoid the development of a gap between them in any of their pivoted positions.

United States Patent Blumenthal l l Nov. 25, 1975 [5 l SUPPORT FOR THE ROOF OF AN 832.741 1/1970 Canada 61/45 D EXCAVATION 839.498 4/1970 Canada 61/45 D [75] Inventor; G'u'nter Blumenthal, Westerholt, Primary Emmmer Dennis L Taylor Germany Attorney. Agent. or Firm-Michael S. Striker [73] Assignee: Bochumer Eisenhutte Heintzmann &

C0.. Bochum Germany [57] ABSTRACT [22] Filed: Feb. 5, 1975 A base has one side facing towards and another side facing away from the face of an excavation. A shield [211 App! 547450 has an end portion that is pivoted to the base in the region of the other side thereof. and it has another end [30] Foreign Application Priority Data portion that is closer to the one side. An adjustable Fgb 15 1974 Germany IIIIIIIIIIIIIIIIIIIIIII N 2407227 support engages the base and the shield for supporting the latter in upright position. An end cap is pivotably [52] U5 CL H 61/45 D; 248/357 mounted on the other end portion of the shield. lnter- [5 H In. C| 2 E2) 15/44 digitating portions are provided on the end cap and on [58] Field of Search 61/45 163,299,' 33' the other end portion of the shield and remain in in- 299l576491l70 Mp; 248/357 terdigitating engagement with one another in pivoted positions of the end cap relative to the other end por- {561 References cued tion of the shield. so as to avoid the development of a gap between them in any of their pivoted positions.

18 Claims, 4 Drawing Figures U.S. Patent Nov. 25, 1975 Sheet 10f2 FIG. 2

US. Patent Nov. 25, 1975 Sheet 2 of2 3,921,409

2 51 f 26 I 27 a 2"? i f A y I SUPPORT FOR THE ROOF OF AN EXCAVATION BACKGROUND OF THE INVENTION The present invention relates to a support for the roof of an excavation, such as a mine or the like.

It is already known to provide supports of this type. hereafter called mine roof supports for the sake of convenience since this is where they are most widely used, with the understanding that the invention is not limited to such a use. Such mine roof supports have a base which extends parallel to the elongation of the mine face and which has pivoted to it, at a side of the base facing away from the mine face, a shield that extends upwardly and in direction towards the mine face, being supported by a pit prop or the like. The free upper end of the shield has pivoted to it an end cap which is to extend to the mine face, or at least to the close proximity thereof, so as to prevent break-in of rock and the like from the roof. Such mine roof supports may be used individually, or a plurality of them may be arranged sideby-side along a mine face. While they have been basically found to be highly advantageous, they do have certain problems which have not yet been overcome by the prior art. When such a mine roof support is to be shifted from one location to another, then the shield and the end cap which is pivoted to its free upper end, must be lowered, for which purpose the pit prop is retracted. As a rule, the portion of the end cap intermediate its pivot connection to the shield and the mine face, i.e., the portion of the end cap that is located forwardly of the pivot connection, is usually longer than the portion of the end cap that is located rearwardly" of the pivot connection. This means that due to the greater weight of the forwardly located portion, the end cap will tilt forwardly and downwardly about its pivot connection to the shield as soon as the shield is retracted. As a result of this, angular movement, whose extent depends upon the length of the rearward portion of the end cap and the vertical distance between the pivot connection of the end cap to the shield and the roof of the mine gallery, rocks and other debris from the roof can drop into the gap which develops between the rear portion of the end cap and the shield. Once the support has been moved to a new location, the pit prop is extended in order to reerect the support. This causes the end cap to be pressed against the roof of the mine gallery and tends to reduce the previously existing angle at which the end cap was inclined to the shield. As a result of this, the debris which had previously dropped into the gap between the rear portion of the end cap and the shield is compressed between them and is squeezed. The pressure that can be exerted by the pit prop (there may be more than one of these provided) usually amounts to several tons, and it is clear that therefore the debris will be strongly compressed and will be so firmly lodged in place that it can be removed only by resorting to mechanized equipment, such as pneumatic hammers or the like. Because of the situations peculiar to underground operations, such conditions as the accumulation and compacting of the debris are not usually immediately recognized, so that the compacting of the material can proceed to a point where it will prevent the pivoting of the end cap relative to the shield; this, of course, defeats to a large extend the purpose of the end cap because the latter can no longer pivotally adjust itself to a positon in which it firmly engages the roof of the mine gallery from below to support it. It can also lead to a deformation of the end cap, and even to damage or breakage of the pivot connection between the end cap and the shield. Further damage to the pivot connection may also result from the fact that fine debris particles can gain access to the pivot connection.

When the aforementioned problems occur, it will be necessary to remove the end cap and, in some highly disadvantageous instances, even the shield itself. and to replace them with new components. This is evidently time consuming and difficult. requiring a large amount of labor and therefore being expensive. Moreover, the roof portions normally supported by the equipment in question must be propped up by other devices. for instance by pit props or the like, during the time during which the repair proceeds, and this, of course, increases the expenses of the operation still further. Depending upon the particular circumstances in a mine gallery, the use of other equipment may not be possible at all, and then operations must be shutdown completely until the support has been repaired.

It is evident that these circumstances cannot be tolerated in the industry. However, heretofore no solutions for overcoming these problems were proposed.

SUMMARY OF THE INVENTION Accordingly. it is an object of this invention to overcome the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide an improved support for the roof of an excavation, which avoids the aforementioned drawbacks.

In keeping with these objects, and with others which will become apparent hereafter. one feature of the invention resides in a support for the roof of an excavation which, briefly stated, comprises a base having one side facing towards, and another side facing away from. the face of an excavation. A shield has one end portion pivoted to the base in the region of the other side, and another portion closer to the one side. An adjustable support engages the base and the shield for supporting the shield in upright position. An end cap is pivotally mounted on the other. end portion of the shield. Interdigitating portions are provided on the end cap and on the other end portion of the shield and remains in interdigitating engagement with one another in pivoted positions of the end cap relative to the other end portion so as to avoid the development of a gap between them in any of the pivoted positions.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partly sectioned side view illustrating a support according to an embodiment of the invention:

FIG. 2 is a top-plan view of the support shown in FIG. 1, when the shield thereof is in retracted position,

FIG. 3 is a section taken on line IIIIII of FIG. 1 on an enlarged scale; and

FIG. 4 is a partly sectioned view, also on an enlarged scale, showing a detail of FIG. I.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1-4 in detail, it will be seen that in FIG. I I have illustrated a support according to the present invention wherein the shield thereof is shown in two positions, namely in the upright or erected position. and in the lowered or retracted position. In FIGS. I and 2. it is clearly shown that the support has a base I; and it should be understood that in these FIGS, the right-hand side of the base I will be facing away from and the left-hand side of the base I will be facing towards the mine face or other excavation face. In the region of the right-hand end portion 2 a shield 4 is connected for pivoting movement about the pivot 3. The shield extends towards the mine face (not shown) and secured to its free end. again for pivoting movement about the illustrated pivot axis, is an end cap 6 which can pivot about a horizontal axis. A pit prop. for example in form of a hydraulic cylinder and piston unit or the like. is identified with reference numeral 7 and is mounted on the base I and on the shield 4, so that it can support the shield in upright position or, when the pit prop 7 is retracted. permit the shield 4 to be lowered. Two or more of these basic supports just described can be arranged in side-by-side relationship. In this case. the bases 1 and/or the shields 4 and- /or the end caps 6 may be connected with one another. Evidently. each of the supports can be provided with one or more of the pit props 7.

The base I of the support illustrated in the drawing has a base plate 8 which extends over its entire length and on which there are mounted vertical supporting plates 9 in the region of its lateral longitudinal edges. The supporting plates 9 are reinforced by reinforcing members I0. Supporting plates 9 extend upwardly in the region of the right-hand end portion 2 of the base so that the pivot 3 for the shield 4 can be mounted in them.

The shield itself is essentially of box'shaped configuration over the greater part of its length. In the center region it is engaged by the pit prop 7 which is here illustrated as a cylinder and piston unit having a cylinder 11 that engages the base I in the region thereof which is closer to the mine face. Reference numerals 12 and 13 identify seats which are engaged by the pit prop 7 on the shield 4 and the base I, respectively. These seats are so configurated that the Iongitidinal axis of the pit prop 7 can assume different angular positions relative to the shield 4 and the base 1, depending upon the length of the pit prop 7, that is the extent to which it has been extended or retracted.

In the illustrated embodiment. the free (left-hand) end portion of the shield 4 is configurated in the manner of a supporting arm. In the illustrated embodiment. two of the shields 4 are located adjacent one another and may be connected to one another by means of screws or the like so as to move in unison. Thus, two of these supporting arms 14 project beyond the center portion 15 of the respective shield 4. The arms 14 are convexly curved at their ends, and the vertical plane in direction towards the excavation face. In their end regions, the arms 4 carry the pivot connection for the end cap 6. The latter has a portion 16 that projects towards the mine face and a portion 17 that projects away from the mine face. The portion 17 is of comb-like construction. having a plurality of portions 18 which interdigitate with the arms I4.

Mounted beneath each of the portions 14 there is secured at substantially box-like structure 19, for example by means of screws or the like. The purpose of these is to serve as reinforcements and it will be seen that in vertical longitudinal section. each of the structures I9 has a configuration which corresponds approximately to the angular range 20 which is defined between the portion 17 of the cap 6 and the arms I4 when the shield 4 is raised to its maximum height (see FIG. I). The structures 19 are essentially triangular and are closed at all sides. Also closed are the end faces 21 of the portions 18. The end faces 21 of the portions I8 and the end faces 22 of the structures I9 are convexly curved in a vertical plane and in direction away from the mine face (compare FIG. I). and the lateral end faces 23 of the center portion 15 of the shield 4. which extend at right angles to the arms 14, are concavely curved in a configuration that mates with the convex curvature (compare FIGS. 1 and 2).

FIG. I shows that when the shield 4 is raised to its highest position. the structures 19 are still located within the cross-sectional area of the arms 14. i.e.. they continue to interdigitate with the arms 14 even in this position.

Gaps 24 exist between the arms 14 and the portions 18, and gaps 2S exist between the end faces 23 and the end faces 21 and 22. To seal these gaps. elastically yieldable sealing strips 26 are provided which' are preferably of synthetic or natural rubber, or an appropriate synthetic elastomer. These sealing strips 26 are also shown in FIG. 3 and are secured to the undersides of the portions 18 and the structures 19 by means of screws or clamps which are well known in the art. They so project that they engage the respectively opposed surface and. when relative movement occurs. wipe over it in the manner of windshield wiper of an automotive vehicle. They thus provide an excellent sealing effect. These strips 26 may be reinforced with metal strips 27, as illustrated. The strips 26 may also be provided on the lateral surfaces of the arms 14 and/or the end faces 23.

FIG. 3 shows most clearly that the portions 18 which are adjacent to the longitudinal sides 28 of the end cap 6, have associated further sealing members 29 with them which rest on the portions l8 and have lateral member 28 that are biased by elastically yieldable spacer members 31. These may for instance be in form of spring-biased pistons or the like. They serve to press the members 29 against cooperating side faces of the adjacent supports. when such supports are arrayed in side-by-side relationship. as illustrated in FIG. 2 for two of such supports. The members 29 are also provided with portions facing away from the mine face and accommodated to the convex curvatures of the end faces 21 and 22.

FIG. 4 shows the region where the end cap 6 is pivoted to the arm 4; in particular, it illustrates a condition in which the shield 4 is so located that the end cap 6 no longer extends parallel to the underside of the roof, but is tilted forwardly and downwardly. In such a situation. the structures 19 would not be sufficient to bridge the gap between the portion 17 and the arm 14, as is the case in FIG. 1. Such situations occur only infrequently and not for prolonged periods of time; to be able to avoid the entry of debris into the portion of the gap 20 that is not protected by the structures I9 in such situations. additional structures 32 analogous to the structures 19 may be provided which are temporarily sccured to the structures 19 below the latter. for instance by means of screws. Once the situation has ceased to exist, it is a simple matter to rapidly disengage the structures 32 from the structures 19, and then to resume normal operations. The structures 32 are also provided with scaling strips 26 provided on their undersides. unless the arms 14 and/or the end faces 23 are themselves provided with such sealing strips 26, in which case sealing strips need not be provided on the structures 32.

It is clear from what has been set forth above that the interdigitation between the end cap 6 and the shield 4 will remain in tact in all pivotal positions of end cap 6 and shield 4, except for the special circumstance in FIG. 4 in which case the interdigitation can. however. be maintained by adding the structures 32. It is now no longer possible for debris to enter into the space and the disadvantages outlined with respect to the prior art are completely avoided. This also eliminates the need for replacement of damaged parts. and the time and labor-consuming replacement work. and even the total shutdown of operations that was sometimes necessary under the circumstances. Thus, continuity of operations is assured and in turn brings with it an improvement in the economy of operations. Also. of course. the present invention greatly enhances the safety of personnel who are required to work beneath the shield 4 and end cap 6 at the face of the excavation.

It will be understood that it is conceivable to provide the interdigitation in some other way. for example by making the structures 19 an integral part of the portion 17 of the end cap 6, rather than separate structures which are mounted on the portion 17. The configration of the structures 19 could also be different from the one illustrated. Evidently. more than one arm 14 could be provided on each shield 4. especially if the shield 4 should be wider than is illustrated in FIG. 2. Where the illustrated example shows two narrow shields 4 in side' by-side relationship.

It is currently preferred that the upper surfaces of each arm 14 merge essentially continuously into the upper surfaces of the portion 17 via their convexly curved free ends. in each relative position of end cap 6 and shield 4. This provides an even more reliable assurancc against the entry. crushing and compacting of debris and assures that the debris will slip downwardly over the shield 4 and cannot interfere with the relative movements of end cap 6 and shield 4.

he free ends of the portions 18 travel in arcuate path when the end cap 6 is pi oted relative to the shield 4. It is for this reason that they are convexly curved and that the cooperating surfaces on the shield 4 are concaveh curved. This makes it possible to maintain the gaps between these surfaces as narrow as possible. Furtiter protection against the passage of dust and small debris through these gaps is. of course. afforded by the scaling strips mentioned earlier in the use of such seallug strips. it is important to take into consideration that the must not oniy provide a sealing action. but also thai they must not oppose any resistance to the relative movements of shield 4 and end cap 6.

it will be understood that each of the elements de scribed abm e. or two or more together. may also find a useful application in other types of constructions differing from the type described above.

While the invention has been illustrated and described as embodied in a support for the roof of an excavation, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis. the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that. from the standpoint of prior art. fairly constitute essential characteristics ofthe generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims is:

l. A support for the roof of an excavation comprising a base having one side facing towards. and another side facing away from. the face of an excavation; a shield having one end portion pivoted to said base in the region of said other side. and another end portion closer to said one side; and adjustable support engaging said base and said shield for supporting the shield in upright position; an end cap pivotably mounted on said other end portion of said shield; and interdigitating portions provided on said end cap and on said other end portion and remaining in interdigitating engagement with one another in pivoted positions of said end cap relative to said other end portion so as to avoid the development ofa gap between them in any of said pivoted positions.

2. A support as defined in claim I, wherein said end cap has a section facing towards and another section facing away from said other end portion. said one section being thicker than said other section and being provided with some of said interdigitating portions.

3. A support as defined in claim 2, said end cap having a lower side facing towards said base and provided on said other section with a plurality of substantially triangular box-shaped structures which increase the thickness of said one section over that of said other section.

4. A support as defined in claim 3, wherein each of said interdigitating portions on said other section has one of said structures mounted thereon.

5. A support as defined in claim 4, wherein said structures are screwed to said interdigitating portions of said other section.

6. A support as defined in claim 3, wherein said other end portion is constituted by at least one supporting arm projecting intermediate two of said interdigitating portions.

7. A support as defined in claim 2, wherein said other end portion is constituted by at least two parallel supporting arms. each projecting intermediate two of said interdigitating portions.

8. A support as defined in claim 6, wherein said other end portion is convexly curved in forward direction. and said arm has an upper surface which merges substantially continuously into an upper surface of said one scction in all pivoted positions of said end cap.

9. A support defined in claim 6, wherein said interdigitating portions and said structures have convexly curved end faces.

10. A support as defined in claim 9, wherein said shield has surface portions extending substantially at right angles to said supporting arm where the latter projects from said shield, said surface portions being concave to mate with the convexly curved end faces of said end cap.

11. A support as defined in claim 9, wherein said end faces and mating surface portions define gaps with one another; and further comprising sealing means sealing said gaps.

12. A support as defined in claim 11, wherein said sealing means comprises elastically yieldable sealing lips provided on at least one of said shield and end cap.

13. A support as defined in claim l2, wherein said sealing lips comprise strips of elastomeric material.

14. A support as defined in claim 13; and further comprising metallic reinforcements for said strips.

tures. 

1. A support for the roof of an excavation comprising a base having one side facing towards, and another side facing away from, the face of an excavation; a shield having one end portion pivoted to said base in the region of said other side, and another end portion closer to said one side; and adjustable support engaging said base and said shield for supporting the shield in upright position; an end cap pivotably mounted on said other end portion of said shield; and interdigitating portions provided on said end cap and on said other end portion and remaining in interdigitating engagement with one another in pivoted positions of said end cap relatIve to said other end portion so as to avoid the development of a gap between them in any of said pivoted positions.
 2. A support as defined in claim 1, wherein said end cap has a section facing towards and another section facing away from said other end portion, said one section being thicker than said other section and being provided with some of said interdigitating portions.
 3. A support as defined in claim 2, said end cap having a lower side facing towards said base and provided on said other section with a plurality of substantially triangular box-shaped structures which increase the thickness of said one section over that of said other section.
 4. A support as defined in claim 3, wherein each of said interdigitating portions on said other section has one of said structures mounted thereon.
 5. A support as defined in claim 4, wherein said structures are screwed to said interdigitating portions of said other section.
 6. A support as defined in claim 3, wherein said other end portion is constituted by at least one supporting arm projecting intermediate two of said interdigitating portions.
 7. A support as defined in claim 2, wherein said other end portion is constituted by at least two parallel supporting arms, each projecting intermediate two of said interdigitating portions.
 8. A support as defined in claim 6, wherein said other end portion is convexly curved in forward direction, and said arm has an upper surface which merges substantially continuously into an upper surface of said one section in all pivoted positions of said end cap.
 9. A support as defined in claim 6, wherein said interdigitating portions and said structures have convexly curved end faces.
 10. A support as defined in claim 9, wherein said shield has surface portions extending substantially at right angles to said supporting arm where the latter projects from said shield, said surface portions being concave to mate with the convexly curved end faces of said end cap.
 11. A support as defined in claim 9, wherein said end faces and mating surface portions define gaps with one another; and further comprising sealing means sealing said gaps.
 12. A support as defined in claim 11, wherein said sealing means comprises elastically yieldable sealing lips provided on at least one of said shield and end cap.
 13. A support as defined in claim 12, wherein said sealing lips comprise strips of elastomeric material.
 14. A support as defined in claim 13; and further comprising metallic reinforcements for said strips.
 15. A support as defined in claim 13, wherein said strips are screw mounted.
 16. A support as defined in claim 13, wherein said strips are clamp mounted.
 17. A support as defined in claim 3, wherein two of said interdigitating portions are located adjacent the respective lateral sides of said end cap; and further comprising sealing elements on said two interdigitating portions.
 18. A support as defined in claim 3; and further comprising box-shaped discrete enlargements on said structures. 